US10865634B2ActiveUtilityA1
Noise robust algorithm for measuring gravitational tool-face
Assignee: HALLIBURTON ENERGY SERVICES INCPriority: Dec 14, 2017Filed: Nov 29, 2018Granted: Dec 15, 2020
Est. expiryDec 14, 2037(~11.4 yrs left)· nominal 20-yr term from priority
Inventors:Rashobh Rajan Sobhana
G01C 21/1654E21B 47/09E21B 47/024E21B 47/022G01C 21/165
63
PatentIndex Score
1
Cited by
15
References
19
Claims
Abstract
A method may comprise penetrating a subterranean formation with a bottom hole assembly, determining a revolutions-per-minute (RPM) measurement based on a zero crossing of sinusoidal magnetometer data, determining a gyroscope bias from gyroscope data using the determined RPM measurement, determining bias compensated gyroscope data by subtracting the determined gyroscope bias from the gyroscope data, determining an angular displacement measurement using the bias compensated gyroscope data, determining a selected tool-face measurement, computing a weighted sum of the selected tool-face measurement with the determined bias compensated gyroscope data, and determining a gravitational tool-face measurement from the computed weighted sum. A system may comprise a drilling rig, a pipe string attached to the drilling rig, a bottom hole assembly attached to the pipe string, wherein the bottom hole assembly comprises at least one sensor, a drill bit, and a computing subsystem connected to the at least one sensor.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method, comprising:
penetrating a subterranean formation with a bottom hole assembly, wherein the bottom hole assembly comprises a drill bit;
determining a revolutions-per-minute (RPM) measurement based on a zero crossing of sinusoidal magnetometer data;
determining a gyroscope bias from gyroscope data using the determined RPM measurement;
determining bias compensated gyroscope data by subtracting the determined gyroscope bias from the gyroscope data;
determining a gyro-based angular displacement measurement using the bias compensated gyroscope data;
computing a first tool-face measurement using the determined RPM measurement;
computing a second tool-face measurement using accelerometer data;
determining a selected tool-face measurement based on a selection between the first tool-face measurement and the second tool-face measurement using a predetermined selection criterion;
computing a weighted sum of the selected tool-face measurement and a gyro-based tool-face measurement;
determining a gravitational tool-face measurement from the computed weighted sum; and
further comprising altering a path of the bottom hole assembly based at least in part on the gravitational tool-face measurement.
2. The method of claim 1 , wherein the gyroscope bias is determined from N gyroscope data samples of the gyroscope data, where N is a positive integer.
3. The method of claim 2 , wherein the gyroscope bias, b′(n), is found with
b
′
(
n
)
=
1
N
∑
i
=
n
-
N
+
1
N
D
(
i
)
-
6
*
R
(
n
)
,
wherein D(i) is the gyroscope data, R(n) is the RPM, n is a sample index, N is the positive integer, and i is a summation index.
4. The method of claim 3 , further comprising averaging the gyroscope bias.
5. The method of claim 1 , wherein the angular displacement measurement is determined by computing an integral operation on a previous calculated bias compensated gyroscope data.
6. The method of claim 1 , wherein the gyroscope bias is determined by estimating the RPM measurement from a magnetic tool-face measurement.
7. The method of claim 1 , wherein the gyro-based angular displacement measurement, Δθ gyro , is found with
Δ
θ
gyro
=
D
′
(
n
)
f
s
,
where D′(n) is the bias compensated gyroscope data, f s is sampling rate, and n a sample index.
8. The method of claim 1 , wherein the first tool-face measurement θ RPM (n), using the determined RPM measurement is found with θ RPM (n)={circumflex over (θ)}(n−1)+Δθ RPM (n) where {circumflex over (θ)}(n) is the gravitational tool-face measurement,
Δθ
RPM
(
n
)
=
R
(
n
)
*
6
f
s
,
where R(n) is the RPM, f s is sampling rate, and n is a sample index.
9. The method of claim 1 , wherein the second tool-face measurement, θ conv (n), using accelerometer data is found with θ conv (n)=a tan(G y (n), −G x (n)), where Gx and Gy are data from, respectively, X and Z-axis accelerometers, and n is a sample index.
10. A system, comprising:
a drilling rig;
a pipe string attached to the drilling rig;
a bottom hole assembly attached to the pipe string, wherein the bottom hole assembly comprises at least one sensor;
a drill bit, wherein the at least one sensor measures a revolutions-per-minute (RPM) of the drill bit; and
a computing subsystem connected to the at least one sensor and configured to:
determine a revolutions-per-minute (RPM) measurement based on a zero crossing of sinusoidal magnetometer data;
determine a gyroscope bias from gyroscope data using the determined RPM measurement;
determine bias compensated gyroscope data by subtracting the determined gyroscope bias from the gyroscope data;
determine a gyro-based angular displacement measurement using the bias compensated gyroscope data;
compute a first tool-face measurement using the determined RPM measurement;
compute a second tool-face measurement using accelerometer data;
determine a selected tool-face measurement based on a selection between the first tool-face measurement and the second tool-face measurement using a predetermined selection criterion;
compute a weighted sum of the selected tool-face measurement and the gyro-based tool-face measurement; and
determine a gravitational tool-face measurement from the computed weighted sum.
11. The system of claim 10 , wherein the at least one sensor is an accelerometer.
12. The system of claim 10 , wherein the computing subsystem is further configured to alter a path of the bottom hole assembly.
13. The system of claim 10 , wherein the computing subsystem is further configured to determine the gyroscope bias from N gyroscope data samples of the gyroscope data, where N is a positive integer.
14. The system of claim 13 , wherein the computing subsystem is further configured to compute the gyroscope bias, b′(n), with
b
′
(
n
)
=
1
N
∑
i
=
n
-
N
+
1
N
D
(
i
)
-
6
*
R
(
n
)
,
wherein D(i) is the gyroscope data, R(n) is the RPM, n is a sample index, N is the positive integer, and i is a summation index.
15. The system of claim 10 , wherein the computing subsystem is further configured to compute the angular displacement measurement with an integral operation on a previous calculated bias compensated gyroscope data.
16. The system of claim 10 , wherein the computing subsystem is further configured to determine the gyroscope bias by estimating the RPM measurement from a magnetic tool-face measurement.
17. The system of claim 10 , wherein the computing subsystem is further configured to compute the gyro-based angular displacement measurement, Δθ gyro , with
Δ
θ
gyro
=
D
′
(
n
)
f
s
,
where D′(n) is the bias compensated gyroscope data, f s is sampling rate, and n is a sample index.
18. The system of claim 10 , wherein the computing subsystem is further configured to compute the first tool-face measurement, θ RPM (n), using the determined RPM measurement with θ RPM (n)={circumflex over (θ)}(n−1)+Δθ RPM (n), where {circumflex over (θ)}(n) is the gravitational tool-face measurement,
Δ
θ
RPM
(
n
)
=
R
(
n
)
*
6
f
s
,
where R(n) is the RPM, f s is sampling rate, and n is a sample index.
19. The system of claim 10 , wherein the computing subsystem is further configured to compute the second tool-face measurement, θ conv (n), using accelerometer data with θ conv (n)=a tan(G y (n), −G x (n)), where Gx and Gy are data from, respectively, X and Y axis accelerometers, and n is a sample index.Join the waitlist — get patent alerts
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